The semiconductor industry is continuously moving toward the fabrication of smaller and more complex microelectronic components with higher performance. The production of smaller integrated circuits requires the development of smaller electronic components, and closer spacing of those electronic components within the integrated circuits. Some integrated circuits include fully depleted semiconductor-on-insulator (FDSOI) substrates that have advantages over substrates that do not include a fully depleted channel, such as reduced short channel effects and reduced parasitic capacitances for transistors. These integrated circuits may utilize a semiconductor-on-insulator (SOI) substrate that has a shallow active layer overlying a buried insulator layer.
Capacitors may be formed using a FDSOI where the capacitor includes an electrically conductive gate and a channel that are separated by an insulating gate dielectric. The capacitance of a capacitor increases with decreased thickness of the dielectric material separating the two conductive materials, and high capacitance is desirable for some functions. Metal/oxide/metal (MOM) capacitors can be formed during back-end-of-the-line (BEOL) processes, but these MOM capacitors typically have relatively thick insulating oxide layers separating the conductive metal layers, which results in a low capacitance.
Capacitors formed earlier in the integrated circuit manufacturing process typically include a conductive gate and channel separated by an insulating gate dielectric, as described above. However, the capacitance of such capacitors tends to vary significantly with an applied voltage. In particular, when the applied voltage changes across certain thresholds, the channel changes from an inversion mode to a depletion mode, where portions of the channel act like an electrical insulator in the depletion mode. The capacitance is much lower in the depletion mode because of the insulating effect of the channel. Therefore the capacitance varies significantly with the voltage. A capacitor with a high capacitance that is independent of the applied voltage allows for greater flexibility in circuit design.
Accordingly, it is desirable to provide integrated circuits including capacitors where the capacitance is less dependent upon the applied voltage, and methods of producing the same. In addition, it is desirable to provide integrated circuits with capacitors that have a high capacitance that remains substantially independent of the applied voltage, and methods of producing the same. Furthermore, other desirable features and characteristics of the present embodiment will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.